Cylinder ridge reamer



Nov. 13, 1934. c. A. OLSON CYLINbER RIDGE H E AMER Filed April 11, 19522 Sheets-Sheet 1 I 1 u 5 w n l Patented Nov. 13, 1934 PATENT OFFICECYLINDER RIDGE REAMER Carl A. Olson, Clarinda, Iowa, assignor to LisleCorporation, Clarmda, Iowa, a corporation of Iowa Application April 11,1932, Serial No. 604,481

4 Claims.

The object of this invention is to provide an improved construction fora tool for reaming and dressing the wall of a cylinder and for removingthe ledge or projection which is commonly formed near one end of thecylinder of an internal combustion engine on account of the fact thatthe uppermost piston ring does not ordinarily travel entirely to the endof the cylinder bore.

A further object of the invention is to provide an improved constructionfor a cylinder ridge reamer having means for causing the operation ofthe reaming or cutting element to conform to the contour of a portion ofthe cylinder wall which is not engaged by said element.

Still another object is to provide an improved cylinder ridge reamerhaving an element adapted to engage and travel on a portion of thecylinder wall during operation of the tool and serving to guide thecutting member in such manner as to cause its cutting operation toconform to the contour of that portion of the wall engaged by saidelement.

Another and further object of the invention is to provide improved meansfor supporting a reaming tool in position for operation upon the wallsof a cylinder and for causing the cutting operation to be performedduring rotary movement of the tool and coincident movement in adirection longitudinally of a cylinder bore.

With these and other objects in view my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in the specification, and illustratedin the accompanying drawings, in which:-

Figure 1 is a plan view, partly in section, illustrating one form of myimproved tool in position for practical use in a cylinder bore.

40 Figure 2 is a side elevation of the tool.

Figure 3 is a vertical section on the line 3-3 of Figure 1, showing thetool in position for use.

Figure 4 is a sectional view similar to a portion of the showing inFigure 3 but illustrating a modified form of guiding means for thecutting element.

Figure 5 is a sectional view showing a piston in its cylinder andillustrating the condition which my improved tool is designed torelieve.

Figure 6'is'a plan view, partly in section, illustrating a modified formof the tool in which a different type of support is employed.

Figure '7 is a vertical section showing the tool of Figure 6 in positionfor operation in the cylinder.

Figure 8 is a vertical sectional view showing a modified form of a toolwhich has some of the same general characteristics as the toolillustrated in Figures 6 and '7.

Figure 9 is a sectional elevation showing a further modified form.

Figure 10 is a longitudinal section of a modified form of carrier memberhaving the cutting element formed directly thereon.

Figure 11 is an elevation of a further modified form of carrier memberin which the guiding means as well as the cutting element are formeddirectly on the carrier member.

This tool is especially designed for dressing the walls of cylinders ofinternal combustion engines which have been in use for some time. It isknown that the constant travel of a piston such as 10 will cause thecylinder walls to be worn to an out of round condition and also leave aledge of ridge 12 at the upper end of the cylinder 14.

The presence of this ridge is occasioned by the fact that the pistonrings do not ordinarily travel entirely to the end of the cylinder bore,and consequently there is not as much wear at this point as upon theportion traversed by the rings.

It is the purpose of this tool to provide means for removing the ledgeor ridge 12 and to perform the operation in such manner that the portionoperated upon will conform to the worn portion of the cylinder wall,Whether or not such worn portion is truly cylindrical. Thus, when a newpiston is installed or when new rings are installed upon an' old piston,the operation of this tool, by removing the ridge referred to, willobviate the condition which might cause a clicking or knocking soundwhen the piston is operated.

In the form shown in Figures 1, 2 and 3, the body of the tool includes atop plate 16 and a bottom plate 18 which are of substantially conicalform and arranged with their points directed toward each other andvariably spaced apart. For adjustably connecting the plates 16 and 18 Iemploy a series of rods 20 which are fixed at their upper ends to thetop plate and which extend slidably through the bottom plate 18.

A series of carriers are arranged to cooperate with the top plate 16 andbottom plate 18 and are movably mounted between them. The carriers areformed tapering at their ends for engagement with the opposed conicalsurfaces of said plates. Two of the carrier members are alike inconstruction and are designated by the numerals 22 and 24 but the othercarrier member 26 is somewhat different. Each carrier member engagesslidably at its upper end in a groove formed between parallel flanges 28on the lower surface of the top plate 16 and each carrier member engagesat its lower end in a groove formed between flanges 30 on the upper faceof the bottomplate 18. It will be observed that these groovedconnections are arranged radially of the device and on inclined linesrelative to its axis, thereby permitting an expansion and contraction ofthe carriers relative to the conical top and bottom plates by radialoutward and inward movement.

The top plate 16 and bottom plate 18 are further connected by a screwheaded bolt 32, upon the threaded lower end of which is mounted a nut34. The head of the bolt 32 is located in an angular recess 36 openingto the top of the plate 16,-and this recess is adapted to receivea-suitable tool such as 38 by means. of which the device may be manuallyrotated. I V

In the lower surface of the bottom plate 18 is formed an angular recess40 adapted to snugly receive the nut 34 and hold it against turning. Anexpansion spring 42 is mounted on the bolt 32 within the recess 40 andbehind the nut 34. If desired, a pin or key 44 may be mounted throughthe lower end of the bolt to prevent accidental removal of the nut 34.'

The carrier members 22, 24 and 26 are formed with outwardly openingrecesses 46 within which rollers 48 are rotatably mounted on verticallyextending pins 50. A separate pin 50 is provided for each of the rollers48 and is mounted in a bore in the carrier member by endwise movement,after which a set screw 52 is placed in the threaded outer end of thebore for the purpose of holding the pin and roller in place. The rollers48 are adapted to travel in contact with the walls of the cylinder 14during the operation of the tool. This contact of the rollers is withthat portion of the cylinder wall which is located beyond the ridge 12,or in other words-that portion which has been worn by previous operationof the piston 10 and its rings.

The carrier member 26 is formed in its outer face with a recess 54 inwhich a cutting or reaming blade 56 is mounted. The blade 56 is mountedrigidly on a laterally extending shank 58 which passes through anopening in the adjacent pin. This particular pin, for convenience indistinguishing it from the others, is designated by the numeral 50' andits roller by-the numeral 48". The bore in which the shank 58 of theblade is mounted extends through the inner face of the carrier member 26and is tapped to receive an adjusting screw 60 which bears against theinner end of the shank. The adjusting screw 60 may be manipulated forregulating the position of the blade 56. After the desired adjustmenthas been achieved it is maintained by tightening the set screw 52 at theouter end of the pin 50', thereby exerting pressure on the end of saidpin and causing it to firmly hold the shank of said blade.

The cutting edge of the blade 56 is in this instance formed at the upperend margin or on the top of the blade and is adapted to operate duringupward movement of the tool. The blade 56 is set and adjusted, by themeans just described, so that the outer end of its cutting edge will bein alignment with the outer periphery of the roler 48, which isimmediately beneath it, whereby the cutting operation of the blade willconform to the surface against which the periphery of the roller 48' istraveling.

The tool is supported by a threaded tubular stem 62 through which theoperating tool 38 may be inserted. The stem 62 is formed at its lowerend with a peripheral flange 64 which is attached to the upper face ofthe head plate 16 by means of screws or the like 66.

Threadedly mounted on the tubular stem 62 is a substantially yoke-shapedbracket 68 whose ends engage on the upper surface of the engine block inwhich the cylinder 14 is formed, and a stop collar and depth gauge 70 ismounted on the ingly held in position with respect to the head plate 16and bottom plate 18 by means of one or more endless coil springs '76encircling said carrier members and preferably mounted in transversegrooves in their outer faces. a

In practical use of this form of the tool, it is placed in positionwithin the upper end of the bore of a cylinder such as 14, the bracket68 having first been moved upwardly on the threaded portion of the stem62. In this connection it should be stated that the threaded mounting ofthe bracket on the stem 62 is preferably by means of a left hand thread.This being true, it follows that when the tool is rotated to the rightby turning the wrench 38, the bracket 68 being held against rotation,the tool with be caused to move upwardly in the bracket.

The tool is inserted within the cylinder bore 14 to such extent that thecutting blade 56 is 10- cated beneath the lower edge of the ridge orledge 12 as indicated in Figure 3. The feet 72 of the yoke 68 are placedon the top of the cylinder block and one of them is caused to engageagainst a stop which may be a stud 74 mounted in one of the threadedopenings which commonly are employed for attaching the cylinderheadtothe block. This engagement is for the purpose of preventing rotarymovement of the bracket 68 as turning movement is applied to the reamingtool in a clockwise direction through turning movement of the operatingtool 38.

A screw driver or the like is then employed for expanding the reamingtool by tightening the bolt 32, it being understood that the nut 34 isheld against rotation by engagement in the recess 40. The screw drivermay be inserted through the tubular stem 62 to engage the slotted headof the bolt 32.

The tightening of the bolt 32 causes the plates 16 and 18 to be drawntoward each other, thereby forcing the tapered carrier members 22, 24and 26 outwardly in their seats against the action of the spring 76.

This tightening action is continued until the peripheries of the rollers48 and 48 engage the inner wall of the cylinder and then is continuedsomewhat past that point, thereby relieving the tension on the spring 76and placing the spring 42 under tension and causing a forcibleengagement of the guiding rollers with the cylinder walls.

The tool is supported with respect to the cylinder 14 by means of thebracket 68 and its feet 72. The rollers 48 and 48 are in engagement withthe worn portion of the cylinder wall and the edge of the cutting blade56 is positioned just below the ledge or ridge 12.

Rotary movement ina clockwise direction is then imparted to the reamermanually by the use of the wrench or tool 38, and this rotary movementcauses the tool to be moved slowly upwardly in the cylinder on accountof the left hand threaded connection of its tubular stem 62 with thesupporting bracket 68, which as before noted is held against clockwiserotary movement. As the tool is rotated and is moved upwardly, thecutting edge of the blade 56 acts to cut and ream away the projectingledge 12 and the operation is continued until the blade has reached thelevel of the upper end of the cylinder and the ridge has been entirelyremoved.

It will be observed that the carrier members are capable of moving onradial lines relative to the axis of the reamer and that their tendencyis to move outwardly on account of the force exerted by the spring 42,which has been placed under compression by tightening the bolt 32. Therollers 48 and 48' consequently are caused to contact at all times withthe surface of the cylinder wall 14 regardless of its contour. Theposition of the roller 48' therefore is always controlled, in operation,by the contour of the wall over which it is traveling and the positionof the cutting blade 56 radially is likewise determined by the samecondition because the outer portion of its cutting edge is in verticalalignment with the outer periphery of the roller 48. It'follows,therefore, that the cut made by the blade 56 in removing the ledge orridge will conform to the surface over which the roller 48' istraveling. This means that the reamed portion of the cylinder wall willconform to the portion below it which is engaged by said roller.Consequently, when new piston rings are installed, these rings willtravel over a surface which conforms, at the upper end of the cylinderbore, with the contour of the worn portion below.

It should be noted that the angular opening for the tool 38 is alwayslocated at the axial center of the reamer, for the carrier members forthe rollers and cutting blade are uniformly spaced and radially arrangedabout the axis of the tool and are caused to move uniformly on radiallines. Considerable expansion of the reamer for work on cylinders ofdifferent diameter may be obtained because of the tapered formation ofthe heads and the ends of the carrier members. The inclined engagementof these members, guided by the flanges 28 and 30, permits easy slidingmovement of the carrier members in expanding and contracting the reamerto the desired diameter and in placing the spring 42 under compressionwhen the tool is confined in a cylinder bore.

The roller 48' which is mounted directly beneath the cutter 56preferably is provided with a felt washer 78 which normally projectsslightly beyond the periphery of the roller. When the tool is in use thewasher '78 is compressed against the cylinder wall and functions toprevent cuttings from the reaming operation from dropping down betweenthe roller and the cylinder wall and becoming rolled upon the wallsurface.

It .will be noted that the roller. 48' serves not only as a guidingmeans for the tool in its contact with the cylinder wall, but that italso has the function of a stop or gauge for the cutting operationinasmuch as it definitely causes the outward or radial extent ofthecutting operation to conform to the surface over which said roller 48'is moving.

In Figure 4 I have shown a slightly modified form of a tool of thistype. This modification in-' volves the use of a carrier member 26'which is formed with an outwardly opening recess 80. In this recess ismounted a cutting blade 82 which functions as in the previouslydescribed construction, by upward movement of the tool. The blade 82 isheld in place by a set screw 84 mounted in the upper end of the carriermember.

According to this construction, a guiding and stop member 86 is employedwhich does not have the characteristics of a roller, but whichpreferably has a rounded outer end arranged for slid-' ing contact withthe cylinder wall. The guiding and stop member 86 is attached directlyto the lower face of the cutting blade 82 as by a screw 88 extendingthrough a slot 90 in said member. The member 86 may be adjusted radiallyrelative to the cutting blade 82 and both members may be adjustedradially in the recess to cause th cut to be made of the desired depth.

Similar compression means is employed as previously described to forcethe carrier member 26 outwardly whereby the guiding and stop member 86is caused to forcibly contact with the cylinder wall. The edge of theblade 82 is, of course, in alignment with the outer end of the member86, thereby requiring that the cut made by said blade shall conform tothe surface over which the rounded outer end of the member 86 istraveling.

In Figures 6 and 7 is illustrated a modified construction in which adifferent form is employed for the body of the tool, and also adifferent means for supporting it although the feeding means is similarto that previously described.

This form of the tool involves a single body member 92 which ischambered to receive a block like carrier member 94 slidably mounted inand projecting from one side of the body member.

The body member. is provided with an upwardly extending stem 96 which inthis instance is of solid rather than tubular construction and is formedat its upper end with an angular projection 98 adapted to be engaged bya socketed wrench or tool for turning the device.

The threads of the stem 96 are likewise of lefthand formation and thisportion of the stem is engaged by the threaded hub 100 of a brackethaving a laterally projecting portion 102 formed with a longitudinalslot 104. The bracket is adapted to be attached rigidly to the top ofthe cylinder block through a cap screw or the like 106 extending throughthe slot 104 and seated in one of the tapped openings in the top of theblock. A split collar 108 is adjustably mounted on the upper part of thestem to serve as a depth gauge after the tool has been set for operationon the first cylinder of a series. The'expanding means which controlsthe position of the carrier member 94 in the housing or body member 92consists of a threaded bolt 110 extending rotatably through a boss 112on the inner end of the body member and having its head engaging theouter face of said boss. The inner end of the bolt 110 has a threadedengagement with the carrier 94. The bolt 110 may be turned in eitherdirection by employing a hand wrench inserted into the cylinder 14 fromabove for engaging the head of the bolt and by this means the carriermember may be expanded or contracted relative to the body member.

The intermediate portion of the bolt 110 is formed with a shoulder 114and a coil spring 116 is mounted on said bolt between the shoulder andthe inner face of the end of the boss 112, thereby providing a yieldingmounting for the carrier member, and permitting the spring to be placedunder compression when the carrier member is expanded or moved outwardlyagainst the wall of the cylinder.

The opposite or outer end portion of the carrier member 94 is formedwith an outwardly opening recess 118 in which a cutting or reaming blade120 is slidably mounted, the blade in this instance being backed by anexpansive coil spring 122 located within the recess.

A guiding roller 124 is also carried by the outer end of the carriermember 94, beneath the blade 120, and having a portion projecting beyondthe end of the carrier member for engagement with the wall of thecylinder such as 14.

To provide a convenient means for adjusting the blade 120 in its seat,so that its outer. edge may be caused to conform to and be in alignmentwith the periphery of the roller 124, I have supplied an adjusting screw126 which has a threaded engagement with the wall of the carrier member94 and which has at its inner end an off center stud 128 projectingwithin and eccentrically of a circular opening 130 in the blade. Theadjusting screw 126 may be turned by the use of a screw driver forcausing the off center stud 128 to engage any desired portion of thewall of the enlarged opening 130, thereby moving the blade 120 inwardlyin the recess 1 18 or permitting it to be moved outwardly under theinfluence of the spring 122.

In practical operation the blade 120 is first adjusted to such positionthat its outer edge is in line with the outer periphery of the roller124, the hub 100 of the bracket is moved upwardly on the threaded stem96, and then the tool is placed in the cylinder to be treated, in such.

manner that the blade 120 is located immediately below the ridge 12. Thetool is properly centered relative to thecylinder 14 in any suitablemanner and then the bracket 102 is rigidly secured the roller and bladefirmly but yieldingly against the cylinder wall.

The reamer is rotated in clockwise direction by means of a wrenchengaging the projection 98, and this rotary movement causes the blade120 and roller 124 to travel over the surface of the cylinder 14. stem96 with the threaded portion of the supporting bracket also causes thetool to be elevated or moved upwardly, and thus the blade 120accomplishes the reaming or cutting away of the ridge 12, the movementbeing continued until the blade reaches the top of the cylinder.

In the operation the cutting element 120 is yieldingly pressed outwardby the spring 122 to the limit of its outward movement as defined by theon center stud 128 of the adjusting screw as previously .described. Theentire .carrier member 94 with the roller and blade are also pressedoutwardly and kept under compression by action of the spring 116 so thatthe roller is caused to forcibly engage the cylinder wall at all timesof the movement of the tool, and the cutting action of the blade 120 iscaused to conform to the travel of the roller 124 on the wall of thecylinder below.

In the form shown in Figure 8 the same type of body member 92 withthreaded stem 96 and The threaded engagement of the and which is causedto bear against the inner face of the boss 112 on the body member, thuschanging the device from a yielding expanding means to a solid expandingmeans.

The carrier member 132 is formed at its opposite end with an end openingrecess 137 in which a blade 138 is slidably mounted and is backed by aspring 140. In this particular form of the tool, as in connection withFigure 4, I have shown a guiding and stopelement 142 which is notrotatably mounted, but which is fixed directly to the blade 138 andwhich slidably engages at its outer end with the wall of the cylinder.The mounting of the guiding element 142 is accomplished by means of ascrew 144 extending through a slot 146 in said element, thus permittingits adjustment relative to the blade for the purpose of aligning theirouter edges.

In this form of the tool the operation is quite similar to thatdescribed in connection with Figures 6 and 7 except that dependance forthe yielding mounting of the blade and for its yielding engagement withthe work is :placed'entirely on the backing spring 140 inasmuch as thecarrier 'member itself is not permitted to move-after it has beenadjusted to such position that the blade 138 and guide 142 are broughtinto forcible contact with the cylinder wall and the spring '140compressed.

As before, the action of the cutting element, in a direction radially ofthe cylinder, is-limited and determined by the engagement of the guidingmember 142 with the cylinder wall below the point of cutting contact andthereby the cutting operation is caused to conform-to the part engagedby said member 142.

In Figure 9 a form offe'eding means is shown, involving a slightlydifferent operation of the cutting element. The same kind of a bodymember 92 is employed having a boss 112 thereon and the expanding screw110 may be such as to involve either the spring pressed or the solidexpanding means of the forms previously described in connection withFigures 6 and '7 on the one hand and Figure 8 on the other.

The body or housing 92 is formed with an up wardly projecting stem 148which is plain, or in other wordsunthreaded-. It engages rotatably inthe plain bearing or hub 150 of a bracket 152,

which is fastened to the top of the cylinder block in the same manner'as the bracket 102 previously described. The stem 148 is formed with anangular projection 154 to which a socketed wrench may be applied forrotating the tool and the hub 1500f the bracket is confined on the stemby a split clamping collar 156.

The housing or body 92 receives slidably a carrier member 158 whichcarries a cutting blade 160 and a guiding roller 162 in line therewith.The cutting element 160 may be slidably mounted and provided with abacking spring as described in connection with some of the previousforms, or it may have a simple adjusting means for causing its outeredge to be aligned with the roller blade 160 is caused to engage theface or inner side of the ridge 112 and it operates by outward movementon a radial line under the influence of the yielding means that may beprovided therefor. It should be borne in mind that this yielding meansmay be in the nature of a compression spring such as 116 (Figure 7) forthe expanding means, or it may be in the nature of a backing spring suchas 122 or 140, or both of such yielding compression means may beemployed if desired.

When the tool shown in- Figure 9 is-rotated, there is of course noupward movement because the threaded connection of the stem with thesupport is omitted. There is simply a rotary movement in the same planeand the cutting operation is caused by outward radial movement of thecutting element 160 as it turns, the cutting action being terminated orlimited by engagement of the roller 162 with the cylinder wall below,thereby causing the cut to conform to that portion of the wall engagedby the roller.

Figures 10 and 11 disclose further modifications with respect to thecarrier member, cutter and stop or guide. These forms of the tool bothapply particularly to the same general type illustrated in Figures 6 to9 inclusive, in which a single carrier member is provided.

In Figure 10 the carrier member is designated as 165 and it is normallyslidably mounted in a housing or body member 116 and may be providedwith an expansion spring 167 backing it. The spring 167 is coiled on anadjusting bolt 168 having a threaded engagement with the carrier memberin a manner similar to that previously described in connection withFigure '7. The spring engages at one end against the house 166 and atits opposite end against a shoulder 169 formed on thebolt.

The carrier member 165 is made of tool steel and is ground in suchmanner as to form an integral cutting element 170 which may operateeither vertically or radially as previously described. This forminvolves a rotatably mounted roller 171 which may be aligned with theouter edge of the cutting element 170. As hereshown the roller 171 iscarried by a separate block 1'72 which is slidably mounted in anoutwardly opening recess 174 in the carrier member and which is providedwith an adjusting screw 1'76 having a threaded connection with thecarrier member. The screw 176 may be adjusted to line up the roller withthe cutting element and in the operation of the tool the action of thecutting element is caused to conform to the surface engaged by saidroller.

The disclosure of Figure 10 involves a new feature or element which itmay be desirable to employ at times. There may be occasions when it isdesirable to use the tool without the yielding expansive means or torender said means inoperative so that a bore may be cut in a truecircle. For this purpose I have provided a set screw 17'? which has atapped seat in the housing 166 and which may be tightened down at timesagainst the carrier member 165. This provides a means for locking thecarrier member and cutting element against the action of the spring 167,to make the yielding expansive means temporarily inoperative. A portionof the ridge immediately above the upper piston ring can be removed inthe regular way to conform 'to the worn part of the cylinder and then bysetting the screw 1'77 and locking the expansive means, the remainder ofthe ridge to the top of the bore can be cut to a true cylindrical shape,and thus conform with the original bore of the cylinder. It is to beunderstood that this locking feature may be employed in connection withother forms of the tool besides the specific form illustrated in Figure10.

According to Figure 11 the carrier member 1'78 is made of tool steel andis again formed with an integral cutting element 180. It is also formedwith an integral guide and stop member 182 which has its outer edge inalignment with the cutting edge of the element 180 and which has asliding engagement with the wall of the cylinder so that the cuttingoperation is caused to conform to the contour of the part engaged by themember 182. The carrier member 178 is provided with an adjusting screw184 having 3 threaded connection therewith and rotatably mounted in thehousing which carries the carrier member in a manner previouslydescribed. The adjusting screw 184 is formed with a shoulder 186 whichis engaged by a compression or expansion spring '188, which is necessaryin this'instance to press the carrier member 178 and its integralelements 180 and 132 into yielding contact with the cylinder wall.

It is obvious from this disclosure that many different modifications maybe employed for accomplishing the purpose of removing the ridge or ledgein such manner that the portion treated will conform to another portionof the cylinder 105 wall which is engaged by a traveling guide memher.

The essential requirements are that suitable supporting means must beemployed for the-tool, permitting it to rotate and permitting thecutting 110 element to be yieldingly advanced toward the work, togetherwith a guide means which travels on a portion of the cylinder wall andwhich is in alignment with the cutting member or with the final positionof the cutting member, to limit the cutting operation so that itconforms to the part engaged by said guide member.

Some of the embodiments of the invention disclose'that the guiding andlimiting functions may be accomplished by the same member and that 120this member may, if desired, be connected directly to the cuttingelement. The different embodiments disclose different ways that thesevarious functions may be accomplished, including the feature of carryingout the cutting operation during upward movement of the tool through athreaded connection with the support.

The different modifications herein illustrated and described are givenas illustrations or examples of difierent means whereby my purposes andobjects may be accomplished and I do not desire to be understood aslimiting myself to any specific structure except as defined by the scopeof the appended claims.

Y I claim as'my invention:

1. In a ridge reaming tool, a body member, a carrier member arranged formovement laterally with respect to the body member, a cutting elementcarried by said carrier member, yielding compression means acting tourge said cutting element outwardly toward the work, means for rotatingthe tool in a cylinder, a part on said carrier member adapted to engagethe cylinder wall below a ridge thereon as the tool is rotated,- tolimit outward movement of the cutting element under the influence ofsaid yielding means, a stationary support, and a threaded connectionbetween said tool and the support for causing the tool to be advanced inthe cylinder as it is rotated 15;)

to remove said ridge and form the portion of the cylinder wall inregistry therewith, with the same contour as the portion below saidridge.

2. In a ridge reaming tool, a body member adapted to be inserted withina cylinder having a ridge near its top end, a carrier member arrangedfor sliding movement laterally with respect to the body member, rotarythreaded means for adjusting said carrier member, a cutting elementslidably mounted for lateral movement relative to said carrier memberand initially positioned below said ridge when said body member isinserted within said cylinder, a backing spring engaging said cuttingelement and urging it toward the cylinder wall, a threaded feeding meanscausing said cutting element to be advanced upwardly, and a membermounted on and carried by said cutting element for engaging the cylinderwall below the ridge thereon, to limit the operation of said cuttingelement under the influence of said spring and thereby form the upperend of the cylinder with the same contour as that portion below saidridge.

, 3. In a cylinder ridge reamer, a body member adapted to be insertedwithin a cylinder, a carrier member arranged for movement relative tothe body member, in a direction radially-of the cylinder, a cuttingelement carried by the carrier member, yielding means adapted to beplaced under compression when said carrier member is expanded, forurging said cutting element toward the work, means for rotating saidbody member and at the same time causing it to advance longitudinally ofthe cylinder for removing a ridge therefrom and a guide and stop membercarried by carrier member and adapted to engage and travel on theportion of the cylinder wall out of alignment with said ridge during themovement of the tool, for guiding the travel of said cutting element andfor limiting its cutting operation to form the portion of the cylinderwall covered by said ridge, with the same contour as said portion out ofalignment therewith.

4. In a tool for reaming a ridge in a cylinder, a bracket adapted to besecured at the top of the cylinder,.a tool body adapted to enter thecylinder, a cutting element carried by the body, yielding means actingto urge said cutting element outwardly toward-the work, a member carriedby the body for engaging the cylinder wall at a point below said ridge,to limit the depth of the cut of said cutting element, a stem on saidbody having a threaded engagement with said bracket, and means forrotating said body, cutting element and limiting member, whereby theyare advanced longitudinally of the cylinder because of such threadedconnection, and said ridge is removed to cause the portion of thecylinder covered thereby to conform to the contour of the portion belowsaid ridge.

CARL A. OLSON.

